This application claims the benefit of Japanese Patent Application No. 2000-151042, filed on May 23, 2000, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a receiver for digital broadcasting, and more particularly, to a receiver that receives a plurality of digital broadcasting waves. Each of the digital broadcast waves is in frame transmission format that includes a synchronization signal and an information data signal. The receiver selects one of the broadcasted waves for reproducing and outputting the signal carried by the selected wave.
2. Description of the Related Art
In digital broadcasting, a frame structure has been adopted as a transmission format to transmit data over the air. The data to be transmitted is divided into a plurality of frames, in particular, data transmission is carried out in a unit of one frame mainly composed of a synchronization signal and a data signal.
On the other hand, a receiver of a digital broadcasting signal receives the signal, demodulates the received signal, and then decodes the signal into data. At the time after decoding the signal, it is necessary for the receiver to detect the start of a frame as a transmission unit of data. In such processing, the synchronization signal of the frame is utilized by the receiver to detect the start of a frame.
However, when a receiver does not receive a synchronization signal, such as in a case of a change in a reception state, the start point of a frame cannot be specified. Without frame synchronization signal detection, the data within a frame cannot be decoded, even though all data signals in the one frame are received.
This problem is especially prevalent in a receiver within a movable body where detection of a synchronization signal becomes difficult with changes in a reception state, for example, changes caused by multi-path waves or fading. In a moving body, the state of electric wave failure within a band selected by the receiver is remarkably changed, and it is therefore difficult to maintain excellent reception and reproduction. As a result, decoding of reception data cannot be suitably carried out, and thus the operability and convenience of the receiver is remarkably degraded.
Accordingly, the present invention is directed to a receiver for digital broadcasting that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
In one aspect of the present invention, a receiver is provided for a digital broadcasting system that receives broadcasting waves of a plurality of frequency bands. When the receiver cannot detect a synchronization signal from a selected band for reproduction, the receiver can decode received data of the selected band by using a synchronization signal of a broadcasting wave in a band other than the selected band.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the receiver for digital broadcasting includes a receiver for receiving a plurality of digital broadcasting waves, wherein each wave has a transmission format made of frames that include a synchronization signal and an information data signal, and the receiver selects one of the broadcasted waves for reproduction. During this process, the respective synchronization signals included in and corresponding to the plurality of respective digital broadcasting waves are first detected. Next, respective timing signals corresponding to the respective detected synchronization signals are generated on the basis of the respective detected synchronization signals. Each of the timing signals correspond to a respective one of the plurality of digital broadcasting waves. The information data signal included in the selected digital broadcasting wave may be extracted and decoded using the timing signal that corresponds to the selected digital broadcasting wave, and the data signal reproduced and outputted. In the case where the synchronization signal cannot be detected from the selected digital broadcasting wave under reproduction, the receiver may create the timing signal corresponding to the selected digital broadcasting wave on the basis of a detected synchronization signal corresponding to at least one of the other received digital broadcasting waves.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention, as claimed.